A liquid crystal display (LCD) has a perfect display effect in the case of no ambient light, but the display effect becomes poor when the ambient light (e.g. sunlight) exists. Therefore, as to the drawback of the LCD, an OLED display apparatus has been developed. The OLED display apparatus includes an anode, a cathode, and an organic emitter layer which is disposed between the anode and the cathode. When the OLED display apparatus operates, an anode hole and a cathode electron are combined in the organic emitter layer, thereby forming an exciton of an electron-hole pair. When the exciton goes back to a ground state, the exciton releases energy for light emission.
Thus, the OLED display apparatus is a self-luminous display apparatus. In comparison with the LCD, visibility and brightness of the OLED display apparatus are higher, and the device can achieve the better display effect when the ambient light exists. Meanwhile, a color filter and a backlight module do not need to be additionally disposed in the OLED display apparatus, so the device further has characteristics of compact size, high contrast ratio, high color saturation, wide viewing angle, high response, low power consumption, and so on.
FIG. 1 is a schematic drawing illustrating an OLED device in the prior art. The OLED device includes a substrate 11, metal cathodes 12, transparent cathodes 13, and organic emitter layers 14 which are disposed between the metal cathodes 12 and the transparent cathodes 13. Furthermore, there are spacers 18 disposed between the different organic emitter layers 14. The metal cathode 12 herein is an opaque Ag electrode. Besides serving as the electrode, the metal cathode 12 further can be utilized to reflect part of the light emitted from the organic emitter layer 14, so that part of the light are emitted from the transparent cathode 13. In order to enhance the light reflection of the metal cathode 12, a reflective layer (not shown in the drawing) can be disposed on a surface of the metal cathode 12. Material of the reflective layer is Ag—Pd—Cu alloy, which consists of silver 90 to 95% by weight, palladium 4 to 8% by weight, and copper about 1% by weight. Production cost of the reflective layer is very high, because the silver of precious metals has a high proportion. Moreover, an alloy system of the Ag—Pd—Cu alloy is a solid solution structure, and metal atoms are distributed as the solid solution in the material. Crystal grains of the silver easily grow abnormally due to a temperature factor in fabricating processes, thus resulting in a rougher surface of the reflective layer. Therefore, an efficiency of the light reflection is influenced, and then the corresponding light outputted efficiency is also influenced.
Therefore, there is a significant need to provide an OLED device and a corresponding display apparatus for solving the problems existing in the prior art.